Pleatco PRB25-IN-TC Replacement Cartridge for Top Load Spa Cartridge, 1 Cartridge Replacement filter for pool and spa cleaning systems 50% open ABS free flow cores maximize water flow through REEMAY filter media Antimicrobial end caps resist chlorine degradation and provide support to filter material for a longer life span 13-5/16-2-1/8-inches with closed top Made in the USA